In recent years, a server virtualization technology has been implemented, in which virtual servers are established on one physical server by software, and in which the virtual servers simultaneously execute processes. If the server virtualization technology is used, a system, in which the virtual servers simultaneously operate on physical servers connected by a communication network, can be established.
The virtual server system, in which the virtual servers operate on the physical servers, is used in a large-scale computing environment, such as in the information system of a data center or a company.
In the information system and the like of a data center or a company using the virtual server system, the installation space, power consumption, and the like tend to increase because the size of the information system increases. Therefore, a significant reduction in the power consumption is required to reduce the cost for maintaining and managing the system and to reduce CO2 which is a global warming factor.
For example, Non Patent Literature 1 describes a technique, in which a management server that manages a virtual server system acquires load data of physical servers and virtual servers, moves the virtual servers to other physical servers to aggregate free resources dispersed over the physical servers, and turns off the power of excess physical servers to reduce the power consumption of the entire virtual server system.
However, in the virtual server system described in Non Patent Literature 1, there is a problem in which the processing time required to determine optimal destinations significantly increases if there are a multiplicity of physical servers that act as possible destinations for the movement of the virtual servers to other physical servers. Therefore, resource insufficiency and unnecessary free resources are generated because the time at which the virtual servers are to be moved is delayed, and the operation efficiency of the virtual server system is reduced.